Diagnosis Of Spinal Muscular Atrophy Research Articles

SMN2 Copy Number Association with Spinal Muscular Atrophy Severity: Insights from Colombian Patients.

Background: Spinal muscular atrophy (SMA) is a genetic neurodegenerative disease primarily affecting paediatric patients, often leading to significant morbidity and mortality. Our principal objective is to describe the sociodemographic characteristics and evaluate the association between the number of SMN2 copies and SMA type in patients from the Colombian Foundation for Spinal Muscular Atrophy (FAMECOL) database. Methodology: An analytical cross-sectional study was conducted on 201 patients with a genetic diagnosis of SMA. Data were identified, extracted, and collected from patient records provided by FAMECOL as patients registered with the association, including 201 patients from April 2013 to April 2024, when the database was delivered. Qualitative variables were described using relative and absolute frequencies, while quantitative variables were described using central tendency and dispersion measures according to their distribution. The association between the SMA type and the SMN2 number of copies was assessed by Fisher's exact test (1 to 5 copies). Results: Of the 201 patients studied, 42% were female (n = 85), and 58% were male (n = 116). The median age was 9 years (IQR 4-16 years). The median age at diagnosis was 9 years (IQR 4-16), varying by subgroup: 2, 7, 14, and 41.5 years for each type, respectively. A total of 25% patients were from Antioquia (n = 51). Eighty-nine per cent had gastrostomy (n = 18). The association between the two variables was statistically significant (p < 0.05). Conclusion: This study highlights SMA clinical variability and its association with the number of SMN2 copies, underscoring the importance of a personalised approach to diagnosing and managing this disease. The findings may guide more effective therapeutic strategies to improve patients' quality of life.

Genotyping sequence-resolved copy-number variations using pangenomes reveals paralog-specific global diversity and expression divergence of duplicated genes.

Copy-number variable (CNV) genes are important in evolution and disease, yet sequence variation in CNV genes is a blindspot for large-scale studies. We present a method, ctyper, that leverages pangenomes to produce copy-number maps with allele-specific sequences containing locally phased variants of CNV genes from NGS reads. We extensively characterized accuracy and efficiency on a database of 3,351 CNV genes including HLA , SMN , and CYP2D6 as well as 212 non-CNV medically-relevant challenging genes. The genotypes capture 96.5% of underlying variants in new genomes, requiring 0.9 seconds per gene. Expression analysis of ctyper genotypes explains more variance than known eQTL variants. Comparing allele-specific expression quantified divergent expression on 7.94% of paralogs and tissue-specific biases on 4.7% of paralogs. We found reduced expression of SMN-1 converted from SMN-2, which potentially affects diagnosis of spinal muscular atrophy, and increased expression of a duplicative translocation of AMY2B . Overall, ctyper enables biobank-scale genotyping of CNV and challenging genes.

Macrostructural Brain Abnormalities in Spinal Muscular Atrophy: A Case-Control Study.

Most individuals with spinal muscular atrophy (SMA) on disease-modifying therapies continue to have chronic motor impairment. Insights into brain involvement in SMA may open new pathways for adjunctive therapies to optimize outcomes. We aimed to characterize macrostructural brain abnormalities detected by MRI in individuals with SMA compared with peer controls. We conducted a cross-sectional case-control study of children and adults with a confirmed genetic diagnosis of 5q SMA, and peer controls matched by age and sex. Brain MRIs acquired on a 3T MRI scanner through a standardized research protocol were reviewed to qualitatively assess the presence of macrostructural changes. The primary outcome was the presence of any structural brain anomaly on MRI. In addition, the total volume of each participant's lateral ventricles was quantified by volumetry using MRIcron. Genetic and clinical variables, including SMN2 copy number and motor function (Hammersmith Functional Motor Scale Expanded and Revised Upper Limb Module scores), were then correlated with neuroimaging findings. A total of 42 participants completed the study (mean age 17.4, range 7-40; 67% male). Of the 21 individuals with 5q SMA, 9 (43%) had macrostructural brain abnormalities identified on MRI compared with 2 of 21 (10%) peer controls (odds ratio 7.1, 95% confidence interval 1.4-34.0). In patients with SMA, the most common structural changes were widening of the arachnoid spaces (n = 4) and ventriculomegaly (n = 4). Individuals with SMA had larger median lateral ventricular volume than their normally developing peers (9.3 mL, interquartile range [IQR] 5.5-13.1 vs 5.3 mL, IQR 3.8-9.8; p = 0.034). Structural brain abnormalities were more frequent in those with 2 SMN2 copies (3/5, 60%) compared with 3 or 4 SMN2 copies (4/10, 40% and 2/6, 33% respectively), not reaching significance. We found no association between structural changes and motor function scores. Individuals with SMA have higher rates of macrostructural brain abnormalities than their neurotypical peers, suggesting CNS involvement in SMA. Understanding changes in the brain architecture of the SMA population can inform the development of adjunct therapies targeting the CNS and potentially guide rehabilitation strategies.

Postnatal management of preterm infants with spinal muscular atrophy: experience from German newborn screening

BackgroundThe introduction of newborn screening (NBS) for spinal muscular atrophy (SMA) has increased the early diagnosis of 5q-associated SMA in presymptomatic and symptomatic preterm infants. National and international recommendations for treating preterms and newborns < 38 weeks of gestational age are unavailable. Our retrospective multicentre study aimed to evaluate the postnatal clinical course of preterm infants with 5q-associated SMA diagnosed since the implementation of NBS in Germany in 2021 and to summarize the German experience regarding the decision-making process for available treatment regimens for preterm infants with ≤ 3 survival of motor neuron 2 (SMN2) copies.ResultsTwelve preterm infants with 5q-associated SMA and a mean gestational age of 34.0 weeks (range: 26.1–36.8) and birth weight of 2022 g (range: 645–3370) were reported from 8/20 German SMA NBS follow-up centers using a pseudonymized questionnaire. Confirmatory diagnosis, including SMN2 copy number, was completed on average on postnatal day 13. All patients had a biallelic deletion of exon 7 or exons 7 and 8 of the survival of motor neuron 1 (SMN1) gene, with SMN2 copy numbers of two in 10 patients and three in two patients. The neonatal course was complicated by respiratory distress due to prematurity (n = 2), sepsis (n = 2), and jaundice (n = 2). At birth, 11 preterm infants (91.6%) were presymptomatic. However, the neurological status of one patient deteriorated at five weeks of age (postconceptional age of 41.8 weeks) prior to the start of treatment. Disease-modifying treatments were initiated in all patients at a mean postconceptional age of 38.8 weeks, with the majority receiving onasemnogene abeparvovec (83.3%, including 2 patients with prior risdiplam bridge therapy). Notably, consensus among participating experts from German neuromuscular centers resulted in 83.3% of patients receiving disease-modifying treatment at term.ConclusionsPremature infants with SMA require interdisciplinary care in close collaboration with the neuromuscular center. SMA NBS facilitates early initiation of disease-modifying therapy, ideally during the presymptomatic phase, which significantly influences the prognosis of the newborn.

SMArt Retro study: a retrospective data analysis of the Russian registry of patients with spinal muscular atrophy

Background. Existing registries of patients with spinal muscular atrophy (SMA) 5q serve as a valuable source of information on identified patients. Information on the characteristics of Russian patients with SMA 5q and the therapy administered in real clinical practice is currently limited.Aim. To describe a cohort of Russian patients with a confirmed diagnosis of SMA 5q and to evaluate patient routing data in real clinical practice settings in Russia.Materials and methods. The present study was a descriptive non-interventional retrospective cohort study in patients diagnosed with SMA 5q who were enrolled in the Russian patient registry between January 1, 2020 and March 31, 2023. Study participants who met the inclusion criteria were automatically identified in the integrated database of the SMA 5q patient registry. Data were uploaded into validated electronic charts, verified and analyzed using descriptive statistics methods. Results. As of March 31, 2023, the Russian SMA registry contained information on 1408 patients from all federal districts and obtained epidemiological, sociodemographic and clinical characteristics of patients, as well as routes to diagnosis and treatment regimens for patients. The median time from disease onset to confirmed diagnosis was 3 months in patients with SMA type 1, 9 months in patients with SMA type 2, 20 months in patients with SMA type 3 and 68 months in patients with SMA type 4. The median time from confirmed diagnosis to the start of disease-modifying therapy was 0.5 months in SMA patients identified by neonatal screening, 21 months in patients with SMA type 1, 59 months in patients with SMA type 2, 47 months in patients with SMA type 3 and 87 months in patients with SMA type 4.Conclusion. This retrospective analysis was carried out in order to identify recent approaches to the diagnosis and treatment of SMA used in real-world clinical practice in Russia. The identified parameters (duration from the disease onset to confirmed diagnosis, duration from the confirmed diagnosis to disease-modifying therapy initiation) indicate that more widespread use of newborn screening and more rapid treatment initiation are unmet needs for SMA patients in Russia.

Emphasis on the importance of comprehensive clinical and genetic analysis - spinal muscular atrophy combined with phenylketonuria: A case report.

Both spinal muscular atrophy (SMA) and Phenylketonuria (PKU) are caused by biallelic pathogenic mutations. However, there has been no report on case who suffering from both diseases simultaneously. SMA mainly affects the motor function while PKU may have an impact on both the intelligence and motor function. But if only 1 disease is treated while neglecting the other, the treatment effect will be compromised. Here, for the first time, we report a case from China diagnosed with both these diseases and treated properly. A boy was admitted to the Children's Hospital Affiliated to Shandong University (Jinan, China) due to "limb weakness for 19 months" when he was 22 months old. Considering that the child's motor function development is delayed, we made a comprehensive examinations including inherited metabolic diseases and found a significantly increase of phenylalanine concentration in the blood which indicating PKU. Combined with his typical clinical manifestations of SMA, target capture sequencing followed by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) technologies were used for genetic confirmation. SMA and PKU was confirmed. The child was treated with risdiplam and low phenylalanine formula immediately when he was diagnosed with both SMA and PKU. The child showed remarkable improvement in motor function and significant decrease of blood phenylalanine concentration after treatment. To our knowledge, this is the first reported case of SMA combined with PKU. This case expands our understanding of diagnosis for synchronous SMA and PKU and highlights the importance of comprehensive examinations and the utilizing of various genetic testing methods to make an accurate diagnosis of genetic diseases, which may help avoiding the progressive damage caused by certain genetic disease with insidious clinical symptoms.

SMN1 c.5C>G (p.Ala2Gly) missense variant, a challenging molecular SMA diagnosis associated with mild disease, preserves SMN nuclear gems in patient-specific fibroblasts.

Spinal muscular atrophy (SMA) is caused by homozygous loss of the SMN1 gene with SMN2 gene copy number correlating with disease severity. Rarely SMA is caused by a deletion on one allele and a pathogenic variant on the other. The pathogenic missense variant c.5C>G (p.Ala2Gly) correlates with a mild disease phenotype that does not correlate with SMN2 copy number. In a mouse model the c.5C>G transgene produces SMN that is thought to form partially functional SMN complexes, but levels in humans have not yet been investigated. We identified two patients with mild SMA caused by a heterozygous deletion of SMN1 and the heterozygous variant, c.5C>G. Molecular findings were confirmed with deletion/duplication analysis and Sanger sequencing. Skin fibroblasts were collected and cultured, and SMN expression was analyzed using immunofluorescence. Two patients with slowly progressing mild weakness were confirmed to have heterozygous pathogenic missense variant c.5C>G and a heterozygous deletion of SMN1. Their clinical presentation revealed much milder disease progression than patients with matched SMN2 copy number. Analysis of the patients' fibroblasts revealed much higher numbers of SMN nuclear complexes than a patient with a homozygous SMN1 deletion and matched SMN2 copy number. These case reports reinforce that the rare c.5C>G variant causes mild disease. Furthermore, the analysis of SMA nuclear gems in patient samples supports the theory that the p.Ala2Gly SMN can form partially functional SMN complexes that may carry out essential cellular functions and result in mild disease.

Communicating the diagnosis of spinal muscular atrophy in endogamous vs. non-endogamous regions

IntroductionThe high prevalence of endogamy, or inbreeding, in northeastern Brazil, is due to historical and cultural factors, with large families living in cities far from the coast and subject to low socioeconomic and infrastructure levels. This breeding practice results in low genetic variability with an increased prevalence of rare autosomal recessive and neurodegenerative diseases, such as spinal muscular atrophy (SMA).ObjectiveUnderstanding the impact of communicating the diagnosis of SMA on the mental health of patients and their families and the differences between the Northeast (endogamous region) and the other regions of Brazil (non-endogamous ones).MethodsCross-sectional study obtained through a structured questionnaire about the moment of receiving the SMA diagnosis, containing the Impact of Event Scale-Revised.Results and discussionThe sample consisted of 100 volunteers from all regions of Brazil, 47 patients diagnosed with SMA and 53 family members present at the time of the diagnosis. There was a predominance of females (83%) and homogeneity between the groups for the variables gender, age, color, education, religion, and SMA subtype (1, 2, 3, and 4). The Northeast region, representing 43% of the sample, despite being less economically favored, showed greater satisfaction with medical care and inclusion in health services, with less self-reported psychological trauma and fewer signs of post-traumatic stress disorder (PTSD) related to the moment of receiving the diagnosis. The non-endogamous regions, in turn, reported the presence of strong waves of emotion, sleep problems, feelings of irritability, anger, and the presence of bad thoughts related to this situation.ConclusionThe feeling of inclusion in health services and satisfaction with medical care in the endogamous region had a positive impact on the mental health of those involved, reducing psychological trauma and signs of PTSD arising from the communication of the SMA diagnosis.

Analytical validation of the amplification refractory mutation system polymerase chain reaction-capillary electrophoresis assay to diagnose spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by homozygous deletion and compound heterozygous mutations in survival motor neuron 1 (SMN1), with severity tied to the copy number of survival motor neuron 2 (SMN2). This study aimed to develop a rapid and comprehensive method for the diagnosis of SMA. A total of 292 children with clinically suspected SMA and 394 family members were detected by the amplification refractory mutation system polymerase chain reaction-capillary electrophoresis (ARMS-PCR-CE) method, which targeted 19 reported mutations, and the results were compared with those in multiplex ligation-dependent probeamplification (MLPA). Individuals with identified point mutations were further confirmed by SMN1 long-range PCR and Sanger sequencing. A total of 202 children with SMA, 272 carriers, and 212 normal individuals were identified in this study. Nodifference was found in the R-value distribution of exons 7 and 8 in SMN1 and SMN2 among these cohorts, with coefficients of variation consistently below 0.08. To detect exon 7 and 8 copy numbers in SMN1 and SMN2, the ARMS-PCR-CE results were concordant with those of MLPA. Approximately 4.95 % (10/202) of the study patients had compound heterozygous mutations. The ARMS-PCR-CE assay is a comprehensive, rapid, and accurate diagnostic method for SMA that simultaneously detects copy numbers of exons 7 and 8 in SMN1/SMN2, as well as 19 point mutations in SMN1 and 2 enhancers in SMN2. This approach can effectively reduce thetime frame for diagnosis, facilitating early intervention and preventing birth defects.

Adherence and Persistence Among Risdiplam-Treated Individuals with Spinal Muscular Atrophy: A Retrospective Claims Analysis.

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by deletions and/or mutations in the survival of motor neuron1 (SMN1) gene. Risdiplam, the first and only oral SMN2 pre-mRNA splicing modifier, is US Food and Drug Administration-approved for the treatment of pediatric and adult patients with SMA. For patients with SMA, long-term adherence to and persistence with an SMA treatment may be important for achieving maximum clinical benefits. However, real-world evidence on patient adherence to and persistence with risdiplam is limited. This retrospective study examined real-worldadherence and persistence with risdiplamfrom a specialty pharmacy in patients with SMA over a 12-month period. Adherence was estimated by using proportion of days covered (PDC) and was calculated over variable (time between first and last fill) and fixed (time from first fill to study period end) intervals. Persistence was defined as no gap in supply ≥ 90days. Patients were included if the time between the index date and study observation period was ≥ 12months, if they initiated risdiplam between August 2020 and September 2022, received ≥ 2 risdiplam fills, and had an SMA diagnosis associated with a risdiplam fill. Subgroup analyses of risdiplam adherence and persistence were performed by age and primary payer type. The proportion of patients (N = 1636) adherent at 12months based on variable and fixed interval PDC was 93% and 79%, respectively. Adherence was high among patients on commercial insurance, Medicaid, or Medicare (range 86-96%). Mean persistence was 330.4days. The highest proportion of patients who were persistent were on Medicaid (81%). These findings demonstrate that patient adherence to and persistence with risdiplam treatment were high, including across all subgroups tested.

Knowledge and Awareness of Spinal Muscular Atrophy in Pre-Marital Health Screenings: A Cross-Sectional Study

Background and Purpose: Early diagnosis of Spinal Muscular Atrophy (SMA) is crucial. This study assesses the awareness and attitudes toward SMA screening among individuals preparing for marriage. Methods: This cross-sectional study was conducted in three family health centers in the central district of XXX from June to September 2023. A researcher-designed 15-item instrument was utilized to collect demographic data and assess knowledge and attitudes regarding SMA among participants aged 18-65, excluding those with a diagnosis of mental retardation. Results: The study was participated in by 197 individuals, with an average age determined to be 29.45±7.48. The proportion of those supporting the implementation of SMA screening was 84.8% (n=167), while the intention to undergo the test was identified at 72.6% (n=143). A significant relationship was found between the willingness to be tested and variables such as the level of education, absence of disabled close relatives, not considering SMA to be genetically inherited, finding screenings appropriate, the perceived impact of test results on marriage, and the belief that screening could not be conducted after marriage. Conclusion: While most recognized SMA's severity, there's a notable deficit in understanding its preventability, suggesting the need for targeted educational interventions to enhance genetic screening uptake.

An Insightful Observation Leading to a Late Diagnosis of Spinal Muscular Atrophy: A Case Report

An Insightful Observation Leading to a Late Diagnosis of Spinal Muscular Atrophy: A Case Report

Screening of Spinal Muscular Atrophy Carriers and Prenatal Diagnosis in Pregnant Women in Yancheng, China.

Spinal muscular atrophy (SMA) is a neuromuscular disorder with an autosomal recessive inheritance pattern. Patients with severe symptoms may suffer respiratory failure, leading to death. The homozygous deletion of exon 7 in the SMN1 gene accounts for nearly 95% of all cases. Population carrier screening for SMA and prenatal diagnosis by amniocentesis for high-risk couples can assist in identifying the risk of fetal disease. We provided the SMA carrier screening process to 55,447 pregnant women in Yancheng from October 2020 to December 2022. Among them, 8185 participated in this process, with a participation rate of around 14.76% (95% CI 14.47-15.06%). Quantitative real-time polymerase chain reaction (qPCR) was used to detect deletions of SMN1 exons 7 and 8 (E7, E8) in screened pregnant women. 127 were identified as carriers (111 cases of E7 and E8 heterozygous deletions, 15 cases of E7 heterozygous deletions, and 1 case of E7 heterozygous deletions and E8 homozygous deletions), resulting in a carrying rate of around 1.55% (95% CI 1.30-1.84%). After genetic counseling, 114 spouses of pregnant women who tested positive underwent SMA carrier screening; three of them were screened as SMA carriers. Multiplexed ligation-dependent probe amplification (MLPA) was used for the prenatal diagnosis of the fetuses of high-risk couples. Two of them exhibited two copies of SMN1 exon 7 (normal), and the pregnancy was continued; one exhibited no copies of SMN1 exon 7 and exon 8 (SMA patient), and the pregnancy was terminated. Analyzing SMN1 mutations in Yancheng and provide clinical evidence for SMA genetic counseling and birth defect prevention. Interventional prenatal diagnosis for high-risk families can promote informed reproductive selection and prepare for the fetus's early treatment.

Carrier Screening and Diagnosis for Spinal Muscular Atrophy Using Droplet Digital PCR Versus MLPA: Analytical Validation and Early Test Outcome.

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular life-threatening disorder. Owing to high carrier frequency, population-wide SMA screening to quantify the copy number of SMN gene is recommended by American College of Medical Genetics and Genomics. An accurate, reliable, short runaround time and cost-effective method may be helpful in mass population screening for SMA. Methods: Multiplex ligation-dependent probe amplification (MLPA) is a gold standard to estimate the copy number variation (CNV) for SMN1 and SMN2 genes. In this study, we validated droplet digital polymerase chain reaction (ddPCR) for the determination of CNV for both SMN1 and SMN2 exon 7 for a diagnostic purpose. In total, 66 clinical samples were tested using ddPCR, and results were compared with the MLPA as a reference test. Results: For all samples, CNV for SMN1 and SMN2 exon 7 was consentaneous between ddPCR and MLPA test results (κ = 1.000, p < 0.0001). In addition, ddPCR also showed a significant acceptable degree of test repeatability, coefficient of variation < 4%. Conclusion: ddPCR is expected to be utilitarian for CNV detection for carrier screening and diagnosis of SMA. ddPCR test results for CNV detection for SMN1/SMN2 exon 7 are concordant with the gold standard. ddPCR is a more cost-effective and time-saving diagnostic test for SMA than MLPA. Furthermore, it can be used for population-wide carrier screening for SMA.

Diagnosis of Challenging Spinal Muscular Atrophy Cases with Long-Read Sequencing

Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disorder primarily caused by the deletion or mutation of the Survival Motor Neuron 1 (SMN1) gene. This study assesses the diagnostic potential of Long-Read Sequencing (LRS) in three SMA patients. For Patient 1, who has a heterozygous SMN1 deletion, LRS unveiled a missense mutation in SMN1 exon 5. In Patient 2, an Alu/Alu-mediated rearrangement covering the SMN1 promoter and exon 1 was identified through a blend of Multiplex Ligation-Dependent Probe Amplification (MLPA), LRS, and Gap-PCR. The third patient, born to a consanguineous family, bore four copies of hybrid SMN genes. LRS determined the genomic structures, indicating two distinct hybrids of SMN2 exon 7-SMN1 exon 8. However, a discrepancy was found between the SMN1-SMN2 ratio interpretations by LRS (0:2) and MLPA (0:4), which suggested a limitation of LRS in SMA diagnosis. In conclusion, this newly adapted long PCR-based third-generation sequencing introduces an additional avenue for SMA diagnosis.

Assessment of Barriers to Referral and Appointment Wait Times for the Evaluation of Spinal Muscular Atrophy (SMA): Findings from a Web-Based Physician Survey.

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by progressive muscle weakness and atrophy. Clinical trial data suggest early diagnosis and treatment are critical. The purpose of this study was to evaluate neurology appointment wait times for newborn screening identified infants, pediatric cases mirroring SMA symptomatology, and cases in which SMA is suspected by the referring physician. Approaches for triaging and expediting referrals in the US were also explored. Cure SMA surveyed healthcare professionals from two cohorts: (1) providers affiliated with SMA care centers and (2) other neurologists, pediatric neurologists, and neuromuscular specialists. Surveys were distributed directly and via Medscape Education, respectively, between July 9, 2020, and August 31, 2020. Three hundred five total responses were obtained (9% from SMA care centers and 91% from the general recruitment sample). Diagnostic journeys were shorter for infants eventually diagnosed with SMA Type 1 if they were referred to SMA care centers versus general sample practices. Appointment wait times for infants exhibiting "hypotonia and motor delays" were significantly shorter at SMA care centers compared to general recruitment practices (p = 0.004). Furthermore, infants with SMA identified through newborn screening were also more likely to be seen sooner if referred to a SMA care center versus a general recruitment site. Lastly, the majority of both cohorts triaged incoming referrals. The average wait time for infants presenting at SMA care centers with "hypotonia and motor delay" was significantly shorter when initial referrals were triaged using a set of "key emergency words" (p = 0.036). Infants directly referred to a SMA care center versus a general sample practice were more likely to experience shorter SMA diagnostic journeys and appointment wait times. Triage guidelines for referrals specific to "hypotonia and motor delay" including use of "key emergency words" may shorten wait times and support early diagnosis and treatment of SMA.

Neurofilament light protein as a biomarker for spinal muscular atrophy: a review and reference ranges.

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality, characterized by progressive neuromuscular degeneration resulting from mutations in the survival motor neuron (SMN1) gene. The availability of disease-modifying therapies for SMA therapies highlights the pressing need for easily accessible and cost-effective blood biomarkers to monitor treatment response and for better disease management. Additionally, the wide implementation of newborn genetic screening programs in Western countries enables presymptomatic diagnosis of SMA and immediate treatment administration. However, the absence of monitoring and prognostic blood biomarkers for neurodegeneration in SMA hinders effective disease management. Neurofilament light protein (NfL) is a promising biomarker of neuroaxonal damage in SMA and reflects disease progression in children with SMA undergoing treatment. Recently, the European Medicines Agency issued a letter of support endorsing the potential utilization of NfL as a biomarker of pediatric neurological diseases, including SMA. Within this review, we comprehensively assess the potential applications of NfL as a monitoring biomarker for disease severity and treatment response in pediatric-onset SMA. We provide reference ranges for normal levels of serum based NfL in neurologically healthy children aged 0-18 years. These reference ranges enable accurate interpretation of NfL levels in children and can accelerate the implementation of NfL into clinical practice.

Design and Validation of a Clinical Outcome Measure for Adolescents and Adult Patients with Spinal Muscular Atrophy: SMA Life Study Protocol.

The objective of this study is to develop a clinical tool for the evaluation and follow-up of adolescent and adult patients with 5q spinal muscular atrophy (SMA) and to design its validation. This prospective, non-interventional study will be carried out at five centres in Spain and will include patients aged 16years or older with a confirmed diagnosis of 5q SMA (biallelic mutation of the survival motor neuron 1 [SMN1] gene). A panel of experts made up of neurologists, physiatrists and Spanish patients' association (FundAME), participated in the design of the clinical tool. Physicians will administer the tool at three time points (baseline, 12months and 24months). Additionally, data from other questionnaires and scales will be collected. Once recruitment is achieved, an interim statistical analysis will be performed to assess its psychometric properties by applying Rasch analysis and classical statistical tests. The tool will consist of up to 53 items to assess functional status from a clinical perspective in seven key dimensions (bulbar, respiratory, axial, lower, upper, fatigability and other symptoms), which will be collected together with objective clinical measures (body mass index, forced vital capacity, pinch strength and 6-minute walk test). The validation of this tool will facilitate the clinical evaluation of adult and adolescent patients with SMA and the quantification of their response to new treatments in both clinical practice and research.

Experience of the treatment of spinal muscular atrophy type 3 Kugelberg-Welander with Nusinersen

Before the advent of pathogenetic therapy, the diagnosis of spinal muscular atrophy (SMA) meant the loss of all hopes for recovery and the patient's setting on the path of a steady decline in motor functions, a deterioration in the quality of life and, ultimately, inevitable early death. Currently, new methods of pathogenetic therapy with nusinersen and risdiplam, as well as etiological therapy with onasemnogene abeparvovec, are available in the Russia. Nusinersen is an antisense oligonucleotide that modifies splicing of the SMN2 gene to increase production of normal full-length motor neuron survival protein, which is deficient in SMA. The mechanism of action of Nusinersen is based on the activation of the disabled exon 7 of the SMN2 gene. The article describes an example of long-term effective treatment using pathogenetic therapy of a patient diagnosed with SMA type 3.

A high-fidelity long-read sequencing-based approach enables accurate and effective genetic diagnosis of spinal muscular atrophy

BackgroundWe aimed to develop a high-fidelity long-read sequencing (LRS)-based approach to detect SMN gene variants in one step. It is challenging for conventional step-wise methods to simultaneously detect all kinds of variations between homologous SMN1 and SMN2. MethodsIn this study, LRS was developed to analyze copy numbers (CNs), full sequences, and structure of SMN1 and SMN2. The results were compared with those from the step-wise methods in 202 samples from 67 families. ResultsLRS achieved 100% (202/202) and 99.5% (201/202) accuracy for SMN1 and SMN2 CNs, respectively. It corrected SMN1 CNs from MLPA, which was caused by SNVs/indels that located in probe-binding region. LRS identified 23 SNVs/indels distributing throughout SMN1, including c.22dup and c.884A > T in trans-configuration, and a de novo variant c.41_42delinsC for the first time. LRS also identified a SMN2 variant c.346A > G. Moreover, it successfully determined Alu-mediated 8978-bp deletion encompassing exon 2a-5 and 1415-bp deletion disrupting exon 1, and the exact breakpoints of large deletions. Through haplotype-based pedigree trio analysis, LRS identified SMN1 2 + 0 carriers, and determined the distribution of SMN1 and SMN2 on two chromosomes. ConclusionsLRS represents a more comprehensive and accurate diagnosis approach that is beneficial to early treatment and effective management of SMA.